Sound-transmitter.



B. F. LEE.

SOUND TRANSMlTTER.

APPLICATION HLED FEB. 9, 1915.

1,176,577. Patented Mar. 21, 1916.

BJYLZEY WW6 I y WWW:

BENJAMIN F. LEE, OF SCHOOLFIELD, VIRGINIA.

SOUND-TRANSMITTER.

Application filed February 9, 1915.

T (LZZ whom it may concern.

Be it. known that I, BENJAMIN F. LEE, a citizen of the United States of America. residing at Schoolfield. in the county of Pittsylvania and State of Virginia, have invented new and useful Improvements in Sound- 'Iransmitters, of which the following is a. specification.

This invention relates to in'iprovcments in sound transmitting devices and has particular application to a telephone transmitter.

As is well known, it is essential that the telephone transmitter should cause the transmission of the sound waves to the receiving end of the line. in such manner that sounds will he reproduced the original In the present form clearly and distinctly.

. f transmitter the reproduced sound waves do not possess the requisite clearness under all conditions, as, for instant-c, when the original sound waves are produced by the speaker talking in a loud tone. This defect. in the transmitter is due to the fa t that the sound waves, when leaving, the speaker-s month. impinge against the diaphra m and i'ionahle characteristic is partially overcome in constructing the. mouth piece. with a perforated bottom disposed over the diaphragm and spaced apart therefrom, such perforated hottom tending to hrealc up the sound waves reflected from the diaphragm;

but, a little consideration will reveal the fact that this pert'm'ated bottom also pre vents a portion of the sound waves from rem-hing the diaphragm and hence pre- 40 vents the. undulations ot' the electric current being commensurate with the original sound waves. Consequently, the sound waves reproduced by the receiver are not equal to the original sound Waves, a portion of the latter have been prevented from impinging against the sound transmitting diaphragm. Therefore, in carrying out the present invention, it is my pt "pose to provide a sound transmitting, diaphragm which will be constructed in such manner that the sound waves will be reflected therefrom at an angle to the original path of the wavesso that the. reflected Waves will not interfere with the incoming Waves and will not w- Spccification of Letters Patent.

Patented Mar. 21, 1916.

Serial No. 7,078.

brate hack and forth between the diaphragm and the source of the waves.

further ohjeet of my invention is to construct a sound transmitting diaphragm for telephone transmitters so that the usual perforated h ttom of the mouth piece may be dispensed with and whereby the sound waves will be reflected from the diaphragm at an angle to the incoming path of the waves and such reflected waves absorbed, thereby increasing the ellieieney of the transmitter and enabling the original sound to he reproduced at the receiving end of the line clear-iv and distinctly.

ll ith the above and other ohjects in view, the invention consists in the construction, combination and arrangement of parts hereinafter set forth in and falling within the sc pe of the claims.

in the. :u'companying drawing; Figure. l is a sectional view through the mouth piece and diaphragi'n of a telephone transn'iitter constru ted in accordance with the present invention. Fig. 2 a similar view taken at right angles to Fig. 1.

Although I have shown and described my invention as applied to a telephone transmitter, I wish it to he understood that the invention, in its useful application, is not limited to this particular purpose, as the same may he en'iploved in connection with other sound transmitters.

Referring now to the drawing in detail. 1 designates a diaphragm constructed of any suitahle material and capable of vibration under the action of sound waves and 2 indicates a cup containing carbon granules connected in an electric circuit and having connection with the diaphragm l atthecentral portion thereof so that as the diaphragm vibrated under the action of the sound waves. an undulatory current will be produced in the transmitting circuit to reproduce the. sounds at the receiving end of the line, as is well known.

3 designates a mouth piece constructed of hard rubber or other ap roved material and having a small open end 4 and a relatively large open end Suitably connected with the small end 4 of the mouth piece 3 and disposed concentrically thereof is an annular plate 6 diverging outwardly from the adjacent end of the mouth piece and having the outer edge thereof in engagement with the marginal edge of the sound trans- .niitting diaphragm 1 and secured to the body of the trsnsniitt r in the usual manner, the outer edge of the plate 6 and the body of the transmitter clamping the peripheral edge of the diaphragm 1 to support the lat ter so that the same may vibrate.

In accordance with my present invention, a cone-shaped block 7 or analogous element secured to the outer face of the diaphragm 1 approximately centrally thereof and has apex projecting toward the mouth piece. 's block 7 is of a diameter at its base proximately equal to the diameter of mouth piece at the small end thereof so that the incoming sound .u'avcs impinge against the side of the cone and he, reflect ed therefrom m. an to the incoming Waves. The inner face of the annular plate 6 is lined with felt or similar material 8 adapted to absorb the sound waves reflected from the sideof the cone.

In practice, the sound strikes the side of the cone-sheped block 'T, as indicated by the arrows in l, and is reflected against the inner face of the plate 6 and as the latter is lined with sound absorbing material, t-he'reflccting sound Waves are taken up and prevented from again. impinging against the diaphragm, thereby eliminating conl'u sion of the sound Waves.

W hile I have herein shown and described the preferred form oi my invention by War" of illus .1 ition, I wish it to be understnor',

do not limit or confine myself to the that I precise details of construction. heroin scribed and clelinented as modification and variation may be made w thin the scope of the claims without duper... u; from the spirit of the invention,

claim:

in a. telephone transmitter, he COfilbi nu 011 with a mouth piece, of an annular n" e secured to the end of the mouth (1 n diaphragm seu r edge the eof, IT-i centrally from the 51ml plate at the diaphragm at an angle to the incoming waves, and means carried hr said plan: for absorbing reflected sou \IEEV:E.

2. Inc telephone traz nation with a mouth pi e oilun plate secured to the small of th piece, a sound transmitting diaphragm cured to said plate at the ouier edge the? means carried by said diuphi J thereof to reflect the sound Waves from th diaphragm at an angle to the incoinin waves, and a felt linin ed to absorb the rcliec In a ieicplzone ire mister, the combination with a mcuh pic-O, of an annular plate secured to the s piece and. alive diaphragm capnh action of sound waves and. plate at the outer edge h shaped block secured at it. an phrngm approxinmtely centrally thereof and of diameter equal to that of the srllill end of said mouth piece whereby the in ing sound waves will he reflected at an outward angle to the original path of said waves.

4. In a telephone transmitter, the combination with a. mouth piece, of an annular plate secured to the smell end of said mouth piece and diverging outwardly tilQlftffOll'x, a diaphragm capable of vibration under tl'uj' action of sound waves and secured to said plate at the outer edge thereof, a cone shaped block secured to said diaphragm an proximately centrally thereof and of 21 diameter equal to that or" the small end of said mouthpiece whereby the incoming sound 'Waves will he reflected at an angle to the original pathof said waves, and means carried by the inner surface of said pixie to absorb the reflected sound. Waves, 7

In testimony odiereof 1 :il n in presence of two Wi nests s .0111, under the =-cnsfed to said 

